Researches on macroscopic fouling behavior and micromorphology are usually conducted separately.In this paper,the relationship between the macroscopic fouling behavior and micromorphology on different materials is est...Researches on macroscopic fouling behavior and micromorphology are usually conducted separately.In this paper,the relationship between the macroscopic fouling behavior and micromorphology on different materials is established.A direct fractal-characterization approach based on the micrographs of calcium carbonate fouling crystals is presented.The box-counting method is used to characterize the fouling crystals.For fractal measurements,t-distribution tests of linear regression hypothesis are performed at the significance level of 0.01.If all listed absolute t-statistics with the minimum of 164 are higher than the corresponding t value,the fouling crystals are determined as fractal,with a confidence level of 99%.The fractal dimensions obtained from the micrographs of different visual fields of a specimen are demonstrated to be almost identical,with maximum and minimum relative values of 4.42%and 0.75%,respectively,and standard deviations ranging from 0.0062 to 0.0266.The irregularity of the crystal morphology indicates larger fractal dimensions.Comparison and analysis of the relationship between macroscopic fouling behavior and micromorphology show that the larger fractal dimension of crystal morphology suggests a small amount of surface fouling.Thus,the reasons for the differences in the macroscopic fouling behaviors of different materials are revealed geometrically.展开更多
To investigate the morphological evolution of the whole growth and aggregation processes of hydrate crystals near the gas–liquid interface,we used a high-pressure visual reactor with high-speed camera to capture the ...To investigate the morphological evolution of the whole growth and aggregation processes of hydrate crystals near the gas–liquid interface,we used a high-pressure visual reactor with high-speed camera to capture the micromorphology of hydrate particles in a natural gas+pure water system with pressure from 2.6 to 3.6 MPa and sub-cooling from 4.7 to 6.23C.The results showed that under low sub-cooling conditions,the amount and size of particles increased first and then decreased in the range of 0–330 lm,and the small particles always dominated.These particles can be roughly classified into two categories:planar flake particles and polyhedral solid particles.Then,the concept of maximum growth dominant particle size was proposed to distinguish the morphological boundary of growth and aggregation.In addition,the micro model was established to better reflect the effects of particle formation process and evolution mechanism near the gas–liquid interface under stirring condition.The results of this study can provide a guidance for flow assurance in multiphase pipeline.展开更多
The surface of a compact disk is analyzed by using SPM and the quantitative micromorphology analysissoftware SPMIAS developed by the author. Images at the same position but with different scanning ranges areobtained u...The surface of a compact disk is analyzed by using SPM and the quantitative micromorphology analysissoftware SPMIAS developed by the author. Images at the same position but with different scanning ranges areobtained under the same experimental conditions. Micromorphology parameters are calculated and compared, andthe relationship between the changing of the scanning range and the changing of micromorphology parameters issummarized.展开更多
During speciation in flowering plants, many morphological characters were evolved in response to continuous selection pressure. Such characters are largely governed by genetic changes or get modulated according to eco...During speciation in flowering plants, many morphological characters were evolved in response to continuous selection pressure. Such characters are largely governed by genetic changes or get modulated according to ecological adaptations. To explore the potential of latter, a novel comparative analysis of seed micromorphology and ultrastructure was performed in twenty species in the genus Dendrobium (Orchidaceae) from well-defined altitude based phytogeographical realms i.e. temperate, subtropical and tropical regions. Seed morphological characteristics from all collected species were examined using 13 quantitative traits descriptors. Comparative seed morphology revealed that the species from temperate region have larger seed volumes and seed volume/embryo volume ratio than species from subtropical or tropical regions irrespective of their phylogenetic association. Hence, phylogenetically related species emphasized their preference for a climatic region as their prime habitat. Similar trends towards gradual increase of percentage free air space were observed in the species of tropical to subtropical and subtropical to temperate regions. The higher percentage of free air space may have an advantage for the species from temperate region with relatively low atmospheric pressure that had greater buoyancy for optimal seed dispersal. Also, phylogenetically distant species from a particular climatic region, showed characteristic features of the testa cell walls sculptured with bead-like orna-mentations or covered with cottony white substances. Based on these observations, it may be concluded that seed volume, % free air space and seed coat ornamentation in Dendrobium species are signatures of adaptation according to climatic preferences rather than their selection during speciation.展开更多
A careful scanning tunneling microscope (STM) observation has been made on the micromorphology structure of the crystal faces for a group of pyrites which include two types of pyrite specimens: natural pyrites, from t...A careful scanning tunneling microscope (STM) observation has been made on the micromorphology structure of the crystal faces for a group of pyrites which include two types of pyrite specimens: natural pyrites, from the different stage of hydrothermal ore deposits and artificial crystal of pyrite. It has been discovered that there is a set of micromorphological structures on the surfaces of pyrite crystals, including pisolitic hillocks, lotus root-like hillocks and spiral steps. This study reveals that the micromorphology of pyrite crystals, which are closely related to thermodynamic conditions and dynamic environment of the ore-forming systems, carries a lot of genetic information.展开更多
The present report describes the development of quantitative and qualitative foliar micromorphological and architectural features in the field environment which elucidated the adaptation of micropropagated plants of P...The present report describes the development of quantitative and qualitative foliar micromorphological and architectural features in the field environment which elucidated the adaptation of micropropagated plants of Passiflora foetida L. in the natural soil conditions. The field environment(high light intensity in comparison to in vitro culture conditions) promotes the autotrophy through decrease in stomatal index(from 23.2 ± 0.15 to 21.0 ± 0.19), increased vein-islets(from 10.0 ± 0.14 to 15.6 ± 0.24 per square millimeters) and veinlet terminations(from 1.6 ± 0.14 to 5.0 ± 0.20 per square millimeters), and trichome density in P. foetida plantlets. The in vitro and field grown leaves mostly possessed anomocytic and anisocytic types of stomata. Two types of trichomes were observed on the surface of leaves of in vitro as well as field transferred plants of P. foetida: the unicellular hairy trichomes(non-glandular), and the multicellular(glandular) trichomes. The trichomes density was less under in vitro conditions as compared to the in vivo environments. The new leaves formed during the ex vitro rooting stage(in greenhouse) and after transplantation of plantlets to the field exhibited the development of adaptive micromorphological features in micropropagated plants, which enabled them to survive under field conditions.展开更多
Nanofluid minimum quantity lubrication(NMQL)is a green processing technology.Cottonseed oil is suitable as base oil because of excellent lubrication performance,low freezing temperature,and high yield.Al_(2)O_(3)nanop...Nanofluid minimum quantity lubrication(NMQL)is a green processing technology.Cottonseed oil is suitable as base oil because of excellent lubrication performance,low freezing temperature,and high yield.Al_(2)O_(3)nanoparticles improve not only the heat transfer capacity but also the lubrication performance.The physical and chemical proper-ties of nanofluid change when Al_(2)O_(3)nanoparticles are added.However,the effects of the concentration of nanofluid on lubrication performance remain unknown.Furthermore,the mechanisms of interaction between Al_(2)O_(3)nanoparti-cles and cottonseed oil are unclear.In this research,nanofluid is prepared by adding different mass concentrations of Al_(2)O_(3)nanoparticles(0,0.2%,0.5%,1%,1.5%,and 2%wt)to cottonseed oil during minimum quantity lubrication(MQL)milling 45 steel.The tribological properties of nanofluid with different concentrations at the tool/workpiece interface are studied through macro-evaluation parameters(milling force,specific energy)and micro-evaluation parameters(surface roughness,micro morphology,contact angle).The result show that the specific energy is at the minimum(114 J/mm^(3)),and the roughness value is the lowest(1.63μm)when the concentration is 0.5 wt%.The surfaces of the chip and workpiece are the smoothest,and the contact angle is the lowest,indicating that the tribological proper-ties are the best under 0.5 wt%.This research investigates the intercoupling mechanisms of Al_(2)O_(3)nanoparticles and cottonseed base oil,and acquires the optimal Al_(2)O_(3)nanofluid concentration to receive satisfactory tribological properties.展开更多
The microscopic characteristics of skeletal particles in rock and soil media have important effects on macroscopic mechanical properties. A mathematical procedure called spherical harmonic function analysis was here d...The microscopic characteristics of skeletal particles in rock and soil media have important effects on macroscopic mechanical properties. A mathematical procedure called spherical harmonic function analysis was here developed to characterize micromorphology of particles and determine the meso effects in a discrete manner. This method has strong mathematical properties with respect to orthogonality and rotating invariance. It was used here to characterize and reconstruct particle micromorphology in three-dimensional space. The applicability and accuracy of the method were assessed through comparison of basic geometric properties such as volume and surface area. The results show that the micromorphological characteristics of reproduced particles become more and more readily distinguishable as the reproduced order number of spherical harmonic function increases, and the error can be brought below 5% when the order number reaches 10. This level of precision is sharp enough to distinguish the characteristics of real particles. Reconstructed particles of the same size but different reconstructed orders were used to form cylindrical samples, and the stress-strain curves of these samples filled with different-order particles which have their mutual morphological features were compared using PFC3D. Results show that the higher the spherical harmonic order of reconstructed particles, the lower the initial compression modulus and the larger the strain at peak intensity. However, peak strength shows only a random relationship to spherical harmonic order. Microstructure reconstruction was here shown to be an efficient means of numerically simulating of multi-scale rock and soil media and studying the mechanical properties of soil samples.展开更多
This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.S...This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.Specifically,softened and slotted bamboo tubes were handled by a roller device with nails to render crack-free flattened bamboo board.Softening temperature and time were optimized herein according to findings regarding chemical composition and board mechanical properties.The optimal softening parameters for saturated steam heat treatment is proved to be 160°C for 8 min.The flattened bamboo board possesses an increased bending strength of 101.5 MPa and a decreased bending modulus of 7.7 GPa,being compared with only-softened bamboo.The corresponding changing mechanism is determined in-depth by the micro-morphological and mechanical results based on in-situ SEM and AFM technologies.Under the action of nails and rolling processes,the bamboo texture becomes compact with crushed and fragmented conduit walls.The resulting cell cavity then becomes stretched and compressed,taking on a morphology which allows for the mechanical penalties associated with flattening to be avoided.According to the micro-mechanical results obtained by AFM,compared with unflatten bamboo,the Young’s modulus of the cell membrane in transverse direction(YT)decreases to 1.00 GPa while the corresponding Young’s modulus in radial direction(YR)increases to 7.29 GPa.展开更多
The strength and durability of concrete will be significantly reduced at high volume of mineral admixture,and the poor early strength of concrete also still needs to be solved.In this investigation,a highly active alk...The strength and durability of concrete will be significantly reduced at high volume of mineral admixture,and the poor early strength of concrete also still needs to be solved.In this investigation,a highly active alkaline electrolyzed waters was used as mixing water to improve the early strength and enhance the durability of green concrete with high volume mineral admixture,the influences of alkaline electrolyzed water(AEW)on hydration activity of mineral admixture and durability of concrete were determined.The results showed that compared with natural tap water,AEW can accelerate early hydration process of cement in concrete and produce comparatively more hydrated products,leading to a 13.6%higher compressive strength than that of ordinary concrete at early age,but the improvement effect of AEW concrete was relatively reduced at long-term age.Meanwhile,the activity of mineral admixtures could be stimulated by AEW to some extent,the strength and durability performance of AEW concrete after double doping 25%slag and 25%fly ash can still reach the level of ordinary cement concrete without mineral admixtures.The SEM micromorphology of 7 d hydrated natural tap water cement paste was observed to be flaky and tabular,but the AEW cement pastes present obvious cluster and granulation phenomenon.The SEM microstructure of AEW concrete with mineral admixtures is more developed and denser than ordinary tap water concrete with mineral admixtures.Therefore,the AEW probably could realize the effective utilization of about 50%mineral admixture amount of concrete without strength loss,the cement production cost and associated CO_(2) emission reduced,which has a good economic and environmental benefit.展开更多
Rain-fed fig culture is known to provide a good quality of dried figs, while almost no research has been reported so far on the enzyme activity comparisons of seasonal variations among terminal buds in this plant. Tow...Rain-fed fig culture is known to provide a good quality of dried figs, while almost no research has been reported so far on the enzyme activity comparisons of seasonal variations among terminal buds in this plant. Toward this goal, we evaluated the physiochemical changes of terminal buds of fig 'Sabz' and their micromorphology during the dormant season(November to April) using Scanning Electron Microscope(SEM) analysis during two consecutive years(2016 and 2017). Results indicated that the highest contents of total sugars in terminal fig buds were registered in January and the lowest values were noticed in April. SEM analysis showed the presence of vegetative terminal fig buds during the dormant season and after bud-break in April. An increasing trend was observed for the protein content, length and diameter of terminal buds at the beginning of bud-break. In dormant buds, ascorbate peroxidase, peroxidase and catalase enzymes exhibited initially an ascending pattern,while it decreased from December. A second increase for these enzymes occurred during the dormant season until bud-break. Superoxide dismutase activity increased in buds during the dormancy season until bud-break. Proline content remained stable in buds from November to February, while it decreased rapidly until bud-break. Furthermore, a downward trend of the total phenol content in buds was observed between the onset and end of dormant period. In general, the dormant buds in 'Sabz' fig cultivar were metabolically active with a short dormant period under the rain-fed conditions.展开更多
Six soils located within the Polish Carpathians,developed on calcium carbonate–rich sedimentary parent materials and representing various reference groups,were investigated in order to detect the lithic discontinuity...Six soils located within the Polish Carpathians,developed on calcium carbonate–rich sedimentary parent materials and representing various reference groups,were investigated in order to detect the lithic discontinuity.We propose using a multidirectional approach to assess the lithic discontinuity in these soils,one that includes grain size distribution,geochemical composition,heavy mineral content and micromorphology,supported by a traditional soil survey.A further aim of this process was to identify the possible admixture of allochthonous material of aeolian origin.The studied soils presented lithic discontinuities mostly at the contact of underlying calcium carbonate–rich coarsegrained slope deposits with the overlaying colluvium layer having a lower content of rock fragments.The significant changes in grain size distribution,especially in the silt and sand content,as well as high Uniformity Values and partially,high Lithological Discontinuity Index values,confirmed the occurrence of a lithic discontinuity in all studied soils.High heterogeneity in the soil profiles was also confirmed by the distribution of the major oxides;however,their distribution did not clearly indicate the lithic discontinuity.The most visible distinctions were noted from CaO content,which resulted from the deposition of carbonate-free materials(aeolian silts)and their mixing with the calcium carbonate–rich parent material.Furthermore,the analysis of heavy mineral content confirmed the allochthonous origin of the upper(and in some cases also the middle)parts of all profiles,which was manifested by the presence of highly weathering-resistant minerals such as zircon,epidote and various types of garnets.The micromorphological features of some of the studied soils showed distinctiveness within the soil profile,manifested by changes in b-fabric pattern,the occurrence and distribution of secondary carbonate and the coarse and fine coarse and fine ratio.Based on the high content of silt within the upper and middle parts of the soils,the content of Hf and Zr,as well as the higher content of weathering-resistant minerals,admixture of aeolian silt could be considered in some of the studied soils,yet with weak character.However,the dominance of minerals typical for metamorphic and igneous rocks suggested that the supply of aeolian silt was associated with loess covers rather than local sedimentary material.展开更多
Negative staining is an effective method that can be used for electron microscopic study to observe fine structural morphology without destruction of bacterial structure. Although uranium acetate is used worldwide as ...Negative staining is an effective method that can be used for electron microscopic study to observe fine structural morphology without destruction of bacterial structure. Although uranium acetate is used worldwide as a general dyeing solution, it is extremely difficult to use it by a new purchase at a research institution because it falls under the nuclear regulation substance in Japan. Therefore, we examined alternative reagents for negative staining that could replace uranium acetate through bacterial observation with an electron microscope. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pyogenes were examined by four stain reagents (phosphotungstic acid (PTA), EMstainer, TI blue, and uranium acetate). Pre cultured bacteria were stained with each stain reagents on a copper grid, washed with PBS, and observed with a transmission electron microscope. In the comparison between bacterial structures, the cell wall structure and bacterial flagella could be observed well in the order of PTA, EMstainer, and uranium acetate. With TI blue staining, flagella could be observed very poorly. In comparison between bacteria, gram negative bacteria such as Escherichia coli and Pseudomonas aeruginosa, could be observed well as compared with gram positive cocci such as Staphylococcus aureus and Streptococcus pyogenes. The uranium acetate looked very coarse in background particles. Since crystals tend to precipitate, TI blue also required filtering, and electron beams were absorbed by the agglomerated crystals, and the frequency of electronic burning occurred high frequency. In this study, there was clear difference in the observation conditions depending on the type of bacteria and the kind of the staining reagents. Especially, it was confirmed that good negative staining features of Pseudomonas aeruginosa by electron microscope were obtained by PTA and EMstainer staining. These alternative reagents are considered to be a candidate for a negative staining.展开更多
A preliminary pharmacognostical and phytochemical evaluation of Smilax domingensis Willd., (Smilacaceae) was realized to determine the macromorphology and micromorphology characteristics, the physicochemical and phyto...A preliminary pharmacognostical and phytochemical evaluation of Smilax domingensis Willd., (Smilacaceae) was realized to determine the macromorphology and micromorphology characteristics, the physicochemical and phytochemical parameters from the rhizome of this spice that grows in Cuba. This crude drug showed the characteristic physicochemical values such as moisture content (13.11%), extractable matter in ethanol at 70% (13.53%), total ashes (3.45%), water soluble ashes (2.43%) and acid insoluble ashes (0.64%). Phytochemical screening revealed the possible presence of alkaloids, oils and/or fats, coumarins, saponins, flavonoids, pyrogallol-type tannins, quinones, catechins, reductants sugars, triterpens and steroids and absence of resins, aminoacids, cardiotonic glycosides, anthocyanidins and astringent and/or bitter principles, realized under WHO parameters.展开更多
[Objectives]To discuss the relationship between left epidermis structures and drought resistance.[Methods]The leaf epidermis of Callisia repens was studied by optical microscope.[Results]The upper and lower epidermal ...[Objectives]To discuss the relationship between left epidermis structures and drought resistance.[Methods]The leaf epidermis of Callisia repens was studied by optical microscope.[Results]The upper and lower epidermal cells of the leaves of Callisia repens arranged closely,and no cell gap was arranged.The morphology of the epidermal cells was hexagonal,few pentagon or heptagon,the equivalent elliptical aspect ratio was 1.20,the vertical wall was straight and there was no stomatal distribution.Compared with the epidermal cells,the morphology of the lower epidermal cells was irregular.The equivalent elliptic aspect ratio was 1.35,and the vertical wall was smooth and curved.The mean oval aspect ratio of the stomatal guard cells was 1.42,the average stomatal density was 11.79/mm 2,and the average stomatal index was 17.21.[Conclusions]These characteristics provide the theoretical basis for the drought resistance of Callisia repens and the ornamental plants as roof greening.展开更多
Santome Shinden, a representative site of the Satoyama landscape in Japan, has its origins in 1696 when the common land of wild grass on the Musashino plateau was developed into a strip-shaped land division, which con...Santome Shinden, a representative site of the Satoyama landscape in Japan, has its origins in 1696 when the common land of wild grass on the Musashino plateau was developed into a strip-shaped land division, which consists of residential area, upland field, and secondary forest. We investigated soils with different land use over 300 years;they are under the secondary forest, and in the upland field where fallen leaves compost derived from secondary forest has been applied continuously for about 300 years since the development. The measured exchangeable cation values suggested that the nutrients in the secondary forest were taken out to the field as fallen leaves. On the surface layer of the upland field soil, characteristic granules of dark brown coated peds (DBC peds) were developed strongly. However, on the surface layer of the secondary forest soil, the DBC peds were not found. Electron probe micro analyzer analysis showed that the outside (dark brown part) of the DBC peds, which was observed only in the upland fields was rich in carbon. The dark brown coated pedofeature was suggested to have an anthropogenic effect due to the long-term application of fallen leaves compost. The anthropogenic activities, which were fallen leaves compost application and cultivation for about 300 years, were thought to affect the soil micromorphology. Therefore, the peds newly found in the Santome shinden field were considered to be a soil microstructure that symbolizes anthropogenic activities.展开更多
The morphology, physicochemical, humic substances and micromorphological characteristics of four soil profiles of the steppe dominant by Festuca lenensis (F. lenensis) at the high mountain and mountain of Khuvsgul, Mo...The morphology, physicochemical, humic substances and micromorphological characteristics of four soil profiles of the steppe dominant by Festuca lenensis (F. lenensis) at the high mountain and mountain of Khuvsgul, Mongolia were studied. Soils were classified as Regosols and Leptosols at high mountain steppe, Leptosols and Cambisols at mountain steppe. On a high mountain, the plant root distribution, OC, N and moisture contents were high due to its high precipitation and low temperature. The soils show immature characteristics with low available nutrients, weakly developed crumb structure, many semi- and undecomposed plant residues, and few little organic pigments with few excrements. The humic acids with immature to degraded characteristics indicate that the climatic condition of high mountains inhibits the soil decomposition process. Due to extremely different landform positions, there a sharp difference was observed between studied soils on high mountain steppe. On the summit with a flat position, the soil of TSO1 showed finer soil texture with higher CEC, exchangeable Mg<sup>2+</sup> and humification degree of SOM compared with the soil of TSO2, which located on the steep slope. This confirms that the abrupt changes in landform on high mountain strongly affect the properties of topsoil. On the mountain steppe, the soil contains higher exchangeable Na<sup>+</sup>, exchangeable K<sup>+</sup> and water soluble at topsoil;however, the plant root distribution, OC, N and moisture contents were lower than that of high mountain soil. Because of warmer air and soil temperature in comparison with that of high elevation, active turnover in humic horizon and chemical weathering process lead to higher available nutrients in mountain steppe. The degraded to well humified characteristics of humic acid, moderately developed crumb structure, a higher component of little organic pigment and many intact excrements indicate that the soil decomposition process and biological activity were higher than that of the high mountain steppe. Our finding suggests that the climatic condition dependent on altitude and landform position at the high mountain and mountain of Khuvsgul had a large impact and played a key role in the soil properties and characteristics of steppe dominant by F. lenensis.展开更多
Dust phenomenon is one of the biggest environmental problems in arid and semiarid regions. In these areas, lakes and wetlands are natural dust traps and core sampling method can be an appropriate way to assess the phe...Dust phenomenon is one of the biggest environmental problems in arid and semiarid regions. In these areas, lakes and wetlands are natural dust traps and core sampling method can be an appropriate way to assess the phenomenon of the dust. Therefore, the purpose of this study is the study of frequency and characteristics of dust sediments in core samples from Hashilan wetlands, Kermanshah. Four intact core samples were taken from different parts of the Hashilan wetland in Kermanshah. Physical, chemical and micromorphological analysis were done. Also clay mineralogy was performed using X-ray analysis (XRD) and shape of particles was photographed by scanning electron microscope (SEM). Considering that four samples had been taken from different parts of the wetland, the quantitative differences in dust amount are likely due to the location of the samples. The results of XRD and thin sections show that the dominant mineralogical composition of dust particles was clay minerals, quartz and calcite. SEM results for core sample 1 revealed that most particles had the size between 2 to 50 mm which ranged from fine silt to coarse silt. Considering the similarities between SEM images for core sample 1 and those from Kermanshah dust measurement station, it could be said that fine rounded particles detected at top 30 cm of core samples had Aeolian origin. These findings were in accordance with the results from dust measurement and weather station of Kermanshah about increased dust activities in the study area over past 10 years.展开更多
基金supported by the National Natural Science Foundation of China“Research on the Mixing Deposition of Crude Oil and Inorganic Salts in Stratified Flow of High Water and Low Oil Through a Pipeline”[grant number 51574259]Research Foundation of China University of Petroleum-Beijing At Karamay(grant number YJ2018B02001).
文摘Researches on macroscopic fouling behavior and micromorphology are usually conducted separately.In this paper,the relationship between the macroscopic fouling behavior and micromorphology on different materials is established.A direct fractal-characterization approach based on the micrographs of calcium carbonate fouling crystals is presented.The box-counting method is used to characterize the fouling crystals.For fractal measurements,t-distribution tests of linear regression hypothesis are performed at the significance level of 0.01.If all listed absolute t-statistics with the minimum of 164 are higher than the corresponding t value,the fouling crystals are determined as fractal,with a confidence level of 99%.The fractal dimensions obtained from the micrographs of different visual fields of a specimen are demonstrated to be almost identical,with maximum and minimum relative values of 4.42%and 0.75%,respectively,and standard deviations ranging from 0.0062 to 0.0266.The irregularity of the crystal morphology indicates larger fractal dimensions.Comparison and analysis of the relationship between macroscopic fouling behavior and micromorphology show that the larger fractal dimension of crystal morphology suggests a small amount of surface fouling.Thus,the reasons for the differences in the macroscopic fouling behaviors of different materials are revealed geometrically.
基金This work was supported by the National Natural Science Foun-dation of China(51974349,U19B2012,51991363)the Natural Science Foundation of Shandong Province(ZR2017MEE057)which are gratefully acknowledged.
文摘To investigate the morphological evolution of the whole growth and aggregation processes of hydrate crystals near the gas–liquid interface,we used a high-pressure visual reactor with high-speed camera to capture the micromorphology of hydrate particles in a natural gas+pure water system with pressure from 2.6 to 3.6 MPa and sub-cooling from 4.7 to 6.23C.The results showed that under low sub-cooling conditions,the amount and size of particles increased first and then decreased in the range of 0–330 lm,and the small particles always dominated.These particles can be roughly classified into two categories:planar flake particles and polyhedral solid particles.Then,the concept of maximum growth dominant particle size was proposed to distinguish the morphological boundary of growth and aggregation.In addition,the micro model was established to better reflect the effects of particle formation process and evolution mechanism near the gas–liquid interface under stirring condition.The results of this study can provide a guidance for flow assurance in multiphase pipeline.
文摘The surface of a compact disk is analyzed by using SPM and the quantitative micromorphology analysissoftware SPMIAS developed by the author. Images at the same position but with different scanning ranges areobtained under the same experimental conditions. Micromorphology parameters are calculated and compared, andthe relationship between the changing of the scanning range and the changing of micromorphology parameters issummarized.
文摘During speciation in flowering plants, many morphological characters were evolved in response to continuous selection pressure. Such characters are largely governed by genetic changes or get modulated according to ecological adaptations. To explore the potential of latter, a novel comparative analysis of seed micromorphology and ultrastructure was performed in twenty species in the genus Dendrobium (Orchidaceae) from well-defined altitude based phytogeographical realms i.e. temperate, subtropical and tropical regions. Seed morphological characteristics from all collected species were examined using 13 quantitative traits descriptors. Comparative seed morphology revealed that the species from temperate region have larger seed volumes and seed volume/embryo volume ratio than species from subtropical or tropical regions irrespective of their phylogenetic association. Hence, phylogenetically related species emphasized their preference for a climatic region as their prime habitat. Similar trends towards gradual increase of percentage free air space were observed in the species of tropical to subtropical and subtropical to temperate regions. The higher percentage of free air space may have an advantage for the species from temperate region with relatively low atmospheric pressure that had greater buoyancy for optimal seed dispersal. Also, phylogenetically distant species from a particular climatic region, showed characteristic features of the testa cell walls sculptured with bead-like orna-mentations or covered with cottony white substances. Based on these observations, it may be concluded that seed volume, % free air space and seed coat ornamentation in Dendrobium species are signatures of adaptation according to climatic preferences rather than their selection during speciation.
文摘A careful scanning tunneling microscope (STM) observation has been made on the micromorphology structure of the crystal faces for a group of pyrites which include two types of pyrite specimens: natural pyrites, from the different stage of hydrothermal ore deposits and artificial crystal of pyrite. It has been discovered that there is a set of micromorphological structures on the surfaces of pyrite crystals, including pisolitic hillocks, lotus root-like hillocks and spiral steps. This study reveals that the micromorphology of pyrite crystals, which are closely related to thermodynamic conditions and dynamic environment of the ore-forming systems, carries a lot of genetic information.
基金financial support to our laboratory as Major Research Project and Grant-In-Aid Scheme (No. 10/DSTE/GIA/RP/JSA-I/2013/213)
文摘The present report describes the development of quantitative and qualitative foliar micromorphological and architectural features in the field environment which elucidated the adaptation of micropropagated plants of Passiflora foetida L. in the natural soil conditions. The field environment(high light intensity in comparison to in vitro culture conditions) promotes the autotrophy through decrease in stomatal index(from 23.2 ± 0.15 to 21.0 ± 0.19), increased vein-islets(from 10.0 ± 0.14 to 15.6 ± 0.24 per square millimeters) and veinlet terminations(from 1.6 ± 0.14 to 5.0 ± 0.20 per square millimeters), and trichome density in P. foetida plantlets. The in vitro and field grown leaves mostly possessed anomocytic and anisocytic types of stomata. Two types of trichomes were observed on the surface of leaves of in vitro as well as field transferred plants of P. foetida: the unicellular hairy trichomes(non-glandular), and the multicellular(glandular) trichomes. The trichomes density was less under in vitro conditions as compared to the in vivo environments. The new leaves formed during the ex vitro rooting stage(in greenhouse) and after transplantation of plantlets to the field exhibited the development of adaptive micromorphological features in micropropagated plants, which enabled them to survive under field conditions.
基金Supported by National Natural Science Foundation of China(Grant Nos.51806112,51975305)PhD Research Startup Foundation of Qingdao University of Technology,China(Grant Nos.JC2022-012,20312008).
文摘Nanofluid minimum quantity lubrication(NMQL)is a green processing technology.Cottonseed oil is suitable as base oil because of excellent lubrication performance,low freezing temperature,and high yield.Al_(2)O_(3)nanoparticles improve not only the heat transfer capacity but also the lubrication performance.The physical and chemical proper-ties of nanofluid change when Al_(2)O_(3)nanoparticles are added.However,the effects of the concentration of nanofluid on lubrication performance remain unknown.Furthermore,the mechanisms of interaction between Al_(2)O_(3)nanoparti-cles and cottonseed oil are unclear.In this research,nanofluid is prepared by adding different mass concentrations of Al_(2)O_(3)nanoparticles(0,0.2%,0.5%,1%,1.5%,and 2%wt)to cottonseed oil during minimum quantity lubrication(MQL)milling 45 steel.The tribological properties of nanofluid with different concentrations at the tool/workpiece interface are studied through macro-evaluation parameters(milling force,specific energy)and micro-evaluation parameters(surface roughness,micro morphology,contact angle).The result show that the specific energy is at the minimum(114 J/mm^(3)),and the roughness value is the lowest(1.63μm)when the concentration is 0.5 wt%.The surfaces of the chip and workpiece are the smoothest,and the contact angle is the lowest,indicating that the tribological proper-ties are the best under 0.5 wt%.This research investigates the intercoupling mechanisms of Al_(2)O_(3)nanoparticles and cottonseed base oil,and acquires the optimal Al_(2)O_(3)nanofluid concentration to receive satisfactory tribological properties.
基金Project(2015CB057903)supported by the National Basic Research Program of ChinaProjects(51679071,51309089)supported by the National Natural Science Foundation of China+2 种基金Project(BK20130846)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(2013BAB06B00)supported by the National Key Technology R&D Program,ChinaProject(2015B06014)supported by the Fundamental Research Funds for the Central Universities,China
文摘The microscopic characteristics of skeletal particles in rock and soil media have important effects on macroscopic mechanical properties. A mathematical procedure called spherical harmonic function analysis was here developed to characterize micromorphology of particles and determine the meso effects in a discrete manner. This method has strong mathematical properties with respect to orthogonality and rotating invariance. It was used here to characterize and reconstruct particle micromorphology in three-dimensional space. The applicability and accuracy of the method were assessed through comparison of basic geometric properties such as volume and surface area. The results show that the micromorphological characteristics of reproduced particles become more and more readily distinguishable as the reproduced order number of spherical harmonic function increases, and the error can be brought below 5% when the order number reaches 10. This level of precision is sharp enough to distinguish the characteristics of real particles. Reconstructed particles of the same size but different reconstructed orders were used to form cylindrical samples, and the stress-strain curves of these samples filled with different-order particles which have their mutual morphological features were compared using PFC3D. Results show that the higher the spherical harmonic order of reconstructed particles, the lower the initial compression modulus and the larger the strain at peak intensity. However, peak strength shows only a random relationship to spherical harmonic order. Microstructure reconstruction was here shown to be an efficient means of numerically simulating of multi-scale rock and soil media and studying the mechanical properties of soil samples.
基金This research was funded by Financial support from the National Natural Science Foundation of China(Nos.61601227,31971740)China Postdoctoral Science Foundation(2017M621598)+4 种基金Nature Science Foundation of Jiangsu Province(BK20160939)Key University Science Research Project of Jiangsu Province(17KJA220004)Jiangsu Agricultural Science and Technology Independent Innovation Project(CX(18)3033)Science and Technology Program of Fujian Province(2019N3014)Open Fund of Key Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo&Rattan Science and Technology(ICBR-2020-08).
文摘This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.Specifically,softened and slotted bamboo tubes were handled by a roller device with nails to render crack-free flattened bamboo board.Softening temperature and time were optimized herein according to findings regarding chemical composition and board mechanical properties.The optimal softening parameters for saturated steam heat treatment is proved to be 160°C for 8 min.The flattened bamboo board possesses an increased bending strength of 101.5 MPa and a decreased bending modulus of 7.7 GPa,being compared with only-softened bamboo.The corresponding changing mechanism is determined in-depth by the micro-morphological and mechanical results based on in-situ SEM and AFM technologies.Under the action of nails and rolling processes,the bamboo texture becomes compact with crushed and fragmented conduit walls.The resulting cell cavity then becomes stretched and compressed,taking on a morphology which allows for the mechanical penalties associated with flattening to be avoided.According to the micro-mechanical results obtained by AFM,compared with unflatten bamboo,the Young’s modulus of the cell membrane in transverse direction(YT)decreases to 1.00 GPa while the corresponding Young’s modulus in radial direction(YR)increases to 7.29 GPa.
基金funded by National Natural Science Foundation of China(Grant Nos.51808310,51878366)Natural Science Foundation of Shandong Province(Grant Nos.ZR2019PEE007,ZR2020ME036)High-level Scientific Research Foundation for the introduction of talent of Qingdao Agricultural University(Grant No.1118034).
文摘The strength and durability of concrete will be significantly reduced at high volume of mineral admixture,and the poor early strength of concrete also still needs to be solved.In this investigation,a highly active alkaline electrolyzed waters was used as mixing water to improve the early strength and enhance the durability of green concrete with high volume mineral admixture,the influences of alkaline electrolyzed water(AEW)on hydration activity of mineral admixture and durability of concrete were determined.The results showed that compared with natural tap water,AEW can accelerate early hydration process of cement in concrete and produce comparatively more hydrated products,leading to a 13.6%higher compressive strength than that of ordinary concrete at early age,but the improvement effect of AEW concrete was relatively reduced at long-term age.Meanwhile,the activity of mineral admixtures could be stimulated by AEW to some extent,the strength and durability performance of AEW concrete after double doping 25%slag and 25%fly ash can still reach the level of ordinary cement concrete without mineral admixtures.The SEM micromorphology of 7 d hydrated natural tap water cement paste was observed to be flaky and tabular,but the AEW cement pastes present obvious cluster and granulation phenomenon.The SEM microstructure of AEW concrete with mineral admixtures is more developed and denser than ordinary tap water concrete with mineral admixtures.Therefore,the AEW probably could realize the effective utilization of about 50%mineral admixture amount of concrete without strength loss,the cement production cost and associated CO_(2) emission reduced,which has a good economic and environmental benefit.
文摘Rain-fed fig culture is known to provide a good quality of dried figs, while almost no research has been reported so far on the enzyme activity comparisons of seasonal variations among terminal buds in this plant. Toward this goal, we evaluated the physiochemical changes of terminal buds of fig 'Sabz' and their micromorphology during the dormant season(November to April) using Scanning Electron Microscope(SEM) analysis during two consecutive years(2016 and 2017). Results indicated that the highest contents of total sugars in terminal fig buds were registered in January and the lowest values were noticed in April. SEM analysis showed the presence of vegetative terminal fig buds during the dormant season and after bud-break in April. An increasing trend was observed for the protein content, length and diameter of terminal buds at the beginning of bud-break. In dormant buds, ascorbate peroxidase, peroxidase and catalase enzymes exhibited initially an ascending pattern,while it decreased from December. A second increase for these enzymes occurred during the dormant season until bud-break. Superoxide dismutase activity increased in buds during the dormancy season until bud-break. Proline content remained stable in buds from November to February, while it decreased rapidly until bud-break. Furthermore, a downward trend of the total phenol content in buds was observed between the onset and end of dormant period. In general, the dormant buds in 'Sabz' fig cultivar were metabolically active with a short dormant period under the rain-fed conditions.
基金financed by the National Science Centre(Poland)(PRELUDIUM 14 project no.2017/27/N/ST10/00342)Ministry of Science and Higher Education of the Republic of Poland,No.BM–4112/17 and BM–2120/18
文摘Six soils located within the Polish Carpathians,developed on calcium carbonate–rich sedimentary parent materials and representing various reference groups,were investigated in order to detect the lithic discontinuity.We propose using a multidirectional approach to assess the lithic discontinuity in these soils,one that includes grain size distribution,geochemical composition,heavy mineral content and micromorphology,supported by a traditional soil survey.A further aim of this process was to identify the possible admixture of allochthonous material of aeolian origin.The studied soils presented lithic discontinuities mostly at the contact of underlying calcium carbonate–rich coarsegrained slope deposits with the overlaying colluvium layer having a lower content of rock fragments.The significant changes in grain size distribution,especially in the silt and sand content,as well as high Uniformity Values and partially,high Lithological Discontinuity Index values,confirmed the occurrence of a lithic discontinuity in all studied soils.High heterogeneity in the soil profiles was also confirmed by the distribution of the major oxides;however,their distribution did not clearly indicate the lithic discontinuity.The most visible distinctions were noted from CaO content,which resulted from the deposition of carbonate-free materials(aeolian silts)and their mixing with the calcium carbonate–rich parent material.Furthermore,the analysis of heavy mineral content confirmed the allochthonous origin of the upper(and in some cases also the middle)parts of all profiles,which was manifested by the presence of highly weathering-resistant minerals such as zircon,epidote and various types of garnets.The micromorphological features of some of the studied soils showed distinctiveness within the soil profile,manifested by changes in b-fabric pattern,the occurrence and distribution of secondary carbonate and the coarse and fine coarse and fine ratio.Based on the high content of silt within the upper and middle parts of the soils,the content of Hf and Zr,as well as the higher content of weathering-resistant minerals,admixture of aeolian silt could be considered in some of the studied soils,yet with weak character.However,the dominance of minerals typical for metamorphic and igneous rocks suggested that the supply of aeolian silt was associated with loess covers rather than local sedimentary material.
文摘Negative staining is an effective method that can be used for electron microscopic study to observe fine structural morphology without destruction of bacterial structure. Although uranium acetate is used worldwide as a general dyeing solution, it is extremely difficult to use it by a new purchase at a research institution because it falls under the nuclear regulation substance in Japan. Therefore, we examined alternative reagents for negative staining that could replace uranium acetate through bacterial observation with an electron microscope. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pyogenes were examined by four stain reagents (phosphotungstic acid (PTA), EMstainer, TI blue, and uranium acetate). Pre cultured bacteria were stained with each stain reagents on a copper grid, washed with PBS, and observed with a transmission electron microscope. In the comparison between bacterial structures, the cell wall structure and bacterial flagella could be observed well in the order of PTA, EMstainer, and uranium acetate. With TI blue staining, flagella could be observed very poorly. In comparison between bacteria, gram negative bacteria such as Escherichia coli and Pseudomonas aeruginosa, could be observed well as compared with gram positive cocci such as Staphylococcus aureus and Streptococcus pyogenes. The uranium acetate looked very coarse in background particles. Since crystals tend to precipitate, TI blue also required filtering, and electron beams were absorbed by the agglomerated crystals, and the frequency of electronic burning occurred high frequency. In this study, there was clear difference in the observation conditions depending on the type of bacteria and the kind of the staining reagents. Especially, it was confirmed that good negative staining features of Pseudomonas aeruginosa by electron microscope were obtained by PTA and EMstainer staining. These alternative reagents are considered to be a candidate for a negative staining.
文摘A preliminary pharmacognostical and phytochemical evaluation of Smilax domingensis Willd., (Smilacaceae) was realized to determine the macromorphology and micromorphology characteristics, the physicochemical and phytochemical parameters from the rhizome of this spice that grows in Cuba. This crude drug showed the characteristic physicochemical values such as moisture content (13.11%), extractable matter in ethanol at 70% (13.53%), total ashes (3.45%), water soluble ashes (2.43%) and acid insoluble ashes (0.64%). Phytochemical screening revealed the possible presence of alkaloids, oils and/or fats, coumarins, saponins, flavonoids, pyrogallol-type tannins, quinones, catechins, reductants sugars, triterpens and steroids and absence of resins, aminoacids, cardiotonic glycosides, anthocyanidins and astringent and/or bitter principles, realized under WHO parameters.
基金Supported by Special Funds for Competitive Allocation Project of Guangdong Provincial Science and Technology Innovation Strategy(2018A03030)Special Talent Program of Lingnan Normal University(ZL2021010).
文摘[Objectives]To discuss the relationship between left epidermis structures and drought resistance.[Methods]The leaf epidermis of Callisia repens was studied by optical microscope.[Results]The upper and lower epidermal cells of the leaves of Callisia repens arranged closely,and no cell gap was arranged.The morphology of the epidermal cells was hexagonal,few pentagon or heptagon,the equivalent elliptical aspect ratio was 1.20,the vertical wall was straight and there was no stomatal distribution.Compared with the epidermal cells,the morphology of the lower epidermal cells was irregular.The equivalent elliptic aspect ratio was 1.35,and the vertical wall was smooth and curved.The mean oval aspect ratio of the stomatal guard cells was 1.42,the average stomatal density was 11.79/mm 2,and the average stomatal index was 17.21.[Conclusions]These characteristics provide the theoretical basis for the drought resistance of Callisia repens and the ornamental plants as roof greening.
文摘Santome Shinden, a representative site of the Satoyama landscape in Japan, has its origins in 1696 when the common land of wild grass on the Musashino plateau was developed into a strip-shaped land division, which consists of residential area, upland field, and secondary forest. We investigated soils with different land use over 300 years;they are under the secondary forest, and in the upland field where fallen leaves compost derived from secondary forest has been applied continuously for about 300 years since the development. The measured exchangeable cation values suggested that the nutrients in the secondary forest were taken out to the field as fallen leaves. On the surface layer of the upland field soil, characteristic granules of dark brown coated peds (DBC peds) were developed strongly. However, on the surface layer of the secondary forest soil, the DBC peds were not found. Electron probe micro analyzer analysis showed that the outside (dark brown part) of the DBC peds, which was observed only in the upland fields was rich in carbon. The dark brown coated pedofeature was suggested to have an anthropogenic effect due to the long-term application of fallen leaves compost. The anthropogenic activities, which were fallen leaves compost application and cultivation for about 300 years, were thought to affect the soil micromorphology. Therefore, the peds newly found in the Santome shinden field were considered to be a soil microstructure that symbolizes anthropogenic activities.
文摘The morphology, physicochemical, humic substances and micromorphological characteristics of four soil profiles of the steppe dominant by Festuca lenensis (F. lenensis) at the high mountain and mountain of Khuvsgul, Mongolia were studied. Soils were classified as Regosols and Leptosols at high mountain steppe, Leptosols and Cambisols at mountain steppe. On a high mountain, the plant root distribution, OC, N and moisture contents were high due to its high precipitation and low temperature. The soils show immature characteristics with low available nutrients, weakly developed crumb structure, many semi- and undecomposed plant residues, and few little organic pigments with few excrements. The humic acids with immature to degraded characteristics indicate that the climatic condition of high mountains inhibits the soil decomposition process. Due to extremely different landform positions, there a sharp difference was observed between studied soils on high mountain steppe. On the summit with a flat position, the soil of TSO1 showed finer soil texture with higher CEC, exchangeable Mg<sup>2+</sup> and humification degree of SOM compared with the soil of TSO2, which located on the steep slope. This confirms that the abrupt changes in landform on high mountain strongly affect the properties of topsoil. On the mountain steppe, the soil contains higher exchangeable Na<sup>+</sup>, exchangeable K<sup>+</sup> and water soluble at topsoil;however, the plant root distribution, OC, N and moisture contents were lower than that of high mountain soil. Because of warmer air and soil temperature in comparison with that of high elevation, active turnover in humic horizon and chemical weathering process lead to higher available nutrients in mountain steppe. The degraded to well humified characteristics of humic acid, moderately developed crumb structure, a higher component of little organic pigment and many intact excrements indicate that the soil decomposition process and biological activity were higher than that of the high mountain steppe. Our finding suggests that the climatic condition dependent on altitude and landform position at the high mountain and mountain of Khuvsgul had a large impact and played a key role in the soil properties and characteristics of steppe dominant by F. lenensis.
文摘Dust phenomenon is one of the biggest environmental problems in arid and semiarid regions. In these areas, lakes and wetlands are natural dust traps and core sampling method can be an appropriate way to assess the phenomenon of the dust. Therefore, the purpose of this study is the study of frequency and characteristics of dust sediments in core samples from Hashilan wetlands, Kermanshah. Four intact core samples were taken from different parts of the Hashilan wetland in Kermanshah. Physical, chemical and micromorphological analysis were done. Also clay mineralogy was performed using X-ray analysis (XRD) and shape of particles was photographed by scanning electron microscope (SEM). Considering that four samples had been taken from different parts of the wetland, the quantitative differences in dust amount are likely due to the location of the samples. The results of XRD and thin sections show that the dominant mineralogical composition of dust particles was clay minerals, quartz and calcite. SEM results for core sample 1 revealed that most particles had the size between 2 to 50 mm which ranged from fine silt to coarse silt. Considering the similarities between SEM images for core sample 1 and those from Kermanshah dust measurement station, it could be said that fine rounded particles detected at top 30 cm of core samples had Aeolian origin. These findings were in accordance with the results from dust measurement and weather station of Kermanshah about increased dust activities in the study area over past 10 years.
